A heavy press for high pressure technology can comprise an upper plate or head plate (head) of the press having an upwardly convex cross section, a lower plate or bed plate (bed) of downwardly convex cross section, a pair of posts between the bed and the head, the frame structure being prestressed against forces developed during press operation by tension members which extend in arcuate patterns around the head and bed and have linear sections lying along the posts.
The tension member can be cables whose opposite ends are held together by stressing or tensioning units, such as hydraulic cylinders, turnbuckles or the like, and the cables can lie in grooves formed in the head, bed and posts.
In general the arcuate bights of the cables along the head and bed are identical and have the configuration of a downwardly open U and an upwardly open U respectively.
Each of the cables applies its prestressing force in a substantially vertical plane and within this plane the space surrounded by the cable forms a stressing section, the stressing sections for all the cables being substantially identical.
A system of this type has been described in German Patent DE PS 28 18 511, FIG. 3, and in this arrangement the tension members cross one another in or on the head of the press.
When this prestressed frame construction is used in heavy presses for high pressure technology, an especially large number of cables and the respective stressing units must be provided to enable the forces to be adequately withstood. It has been difficult if not impossible to provide an adequate number of such cables in presses for certain purposes.
Furthermore, the crossing configuration of the cables tends to place an undue stress on them which might limit the ability of the stressing system to withstand the press-generated forces.